Formation thief



L. H. PERRY ET AL FORMATION THIEF Filed June 2i, 1926 Inventor's, LeroyPerry and Walter I. Woodman, Wy

J attorney.

Patented July 12, 1927.

AND WALTER r. woonmau, or tone 3mm], camroaum. I

LEROY H. PERRY, OF GARDENA,

reason i FORMATION THIEF.

Application filed June 21,

-In this specification, and the accompanying drawing, we will describeand show a preferred form of our invention, and specifically mentioncertain of its more important objects. We do not limit ourselves to theforms disclosed, since various changes "and adaptations may be madetherein without departing from the essence of our invention ashereinafter claimed; and objects and advantages, other than thosespecifically mentioned, are included within its scope.

Our invention relates to means for obtaining samples of the penetratedformation in deep wells and the like. Its principal objects include;first, to provide a device adapted for obtaining samples of materialfrom the walls of drilled wells at any desired depth; second, to providepositive means for taking said samples at a pre-de- 2 termined distanceabove the bottom of the well; and, third, to accomplish the statedobjects by means of a simple and relatively inexpensive device that isada'pte'd'for use with both rotary and standard drilling rigs. Ourobjects are attained in the manner illustrated in the accompanyingdrawing,

in which- Figure 1 is an elevation of our invention in centrallongitudinal section;

Figure 2 is'an elevation of the plunger of the tool with its lower endbroken away to show its interior construction; and

' Figure 3 is an enlarged elevation of one of the thieves'of the devicein central longitudinal section.

Similar reference numerals referto similar parts throughout the severalviews.

In the drilling'of deep wells it frequently is of the greatestimportance to obtain an accurate knowledge of the formation that hasbeen passed through. Thus, in plugging back a hole that has been drilledtoo deep, it is essential to know what formation the pipe is beingcemented into. It often happens that in coring operations a fullrecovery of the core is not obtained, and the formation record is thuslost or is incomplete. Our device permits of sampling the formation inthe walls of a drilled well at any desired depth, and of positivelyrecovering 'such samples.

Our invention comprises a tubular housing 40f slightly less diameterthan the bore of the well- The lower end of the housing 1926. Serial No.117,629.

is fitted with a bushing 5 having a concaved upper surface 6, an axialcirculation passage 7, and a. screw pin 8 for attaching tool-joints orpipe at its lower extremity. At the T- end of the housing is a somewhatsimr bushing 9 which is removable for assembli and disassemblingpurposes, and whicl' is i provided with'a co-axial seat for a squareshaft adapted to reciprocate therethr o'u'gh.

Within the housing are a plurality.=-of" curved barsprings 10 havingtheir up'pe'r extremities attached to the housing wall, as

at 11, and provided with sampling thieves 12 mounted at their free ends.The housing" I is pierced with holes 13 sufficiently llJI'gQjliO- allow'the thieves to extend through the;

walls to positions shown dotted at'l l, when the springs are pressedoutwardly. The.

embodiment of our invention illustrated wis provided with eight suchthieves distributed I helically upon the housing.

The thieves are adapted for being pressed outwardly by means of aplunger 15 having a convex nose 16, adapted. for seating upon surface 6,and which may be reciprocated within the housing by means of the squareshaft 17 which passes upwardly through bushing .9. A screw pin 18 at thetop of the square shaft permits of suspending the whole device from adrill collar at the bottom of a tool string. The plunger and squareshaft are axially bored for water circulation purposes, but bore 19 ofthe plunger terminates short of its lower extremity and has two or morelateral. outlets 20 discharging at the convex surface of its nosenearthe point. The location of these outlets is such that they will beeffectively closed when the plunger 'm seated upon surface 6. I I

The thieves 12 ordinarily are cup-shaped, with cutting edges 21 at theirrims. There are one or more circumferential shoulders 22 on their innersurfaces for retaining the plugs of material that enter, and an axialhole 23 at the'base of the cup permits water and mud to escape beforethe incoming material. The thieves are provided with screwthreadedshanks 24, and are screwed into correspondingly tapped holes in the freeextremities of springs 10. i r

The method of operating our device may be illustrated as follows. Thedistance from the bottom of the well to the point where samples are tobe taken from'the wall is first determined, and sufficient pipe isattached to pin 8 to permit of taking these samples when the pipe isbottomed in the well. is then lowered in .the weltsuspended from a toolstring, and with the circulation pump running and dischargingthroughpassages 20. As soon as the pipe at the lower end of the device bottomsin the well, the plunger 15 will descend within the housing and forceall of the thieves outwardly and into the formation of the side walls ofthe well. When the plunger seats itself upon surface 6 the circulationfrom the pumps through passages 20 is immediately shut oflland this willafford a positive indication that the thieves have been pressedoutwardly at the proper point into the side wall formation. The toolstring may then be pulled upwardly to raise plunger 15 until it engagesbushing 9. The tool can then be Withdrawn from the well since thethieves will have been retracted by their springs 10. WVhen the thievesare examined after withdrawal it will be found that they contain plugsof material comprising the formation of the side walls of the well atthe points sampled.

We desire to point out'particularly that the pump circulation can notbeshut off until plunger 15 has seated upon surface 6 and ever thief hasbeen forced outwardly into the ormation. This gives the operatorpositive assurance that the device has functioned properly at thedesired point in the well.

Having thus fully described our invention weclaim: q

1. A device of the character described comprising; a tubular housinghaving lateral apertures; sampling thieves resiliently mounted withinthe housing; and means for pressing said thieves outwardly through saidapertures.

2. A device of the character described comprising; a tubular housinghavinglateral apertures; sampling thieves resiliently mounted within thehousing; and a reciprocal plunger within the housing adapted forpressing said thieves outwardly through said apertures.

3. A device of the character described comprising; a tubular housinghaving lat- The tool,

eral apertures; arcuate springs terminally.-

attached to the interior wall of the housing with free ends oppositesaid apertures; sampling thieves adapted for extending through theapertures mounted on the outer side of said free ends; and a reciprocalplunger within the housing adapted for pressing said free ends outwardlyto cause the thieves to project beyond the housing.

4. A device of the character described comprising; a cylindrical housinghaving lateral apertures; a lower bushing in the housing having acentral orifice therethrough and an inner seating surface surroundingthe orifice; sampling thieves resiliently mounted within the housing;and a plunger reciprocally mounted within the housing adapted forpressing said thieves outwardly through saidapertures, and for thenbecoming seated upon said surface; said plnngerhaving a circulatingpassage therethrough having outlets at its seating surface only.

5. A device of the character described comprising; a cylindrical housinghaving lateral apertures and a head with an inner concave seatingsurface thereon; sampling thieves resiliently mounted within thehousing; and a reciprocal plunger with a'convex nose within the housingadapted for pressing said thieves outwardly through said apertures, andfor then seating its nose upon said surface; said plunger having a stemextending through the other head of the housing; and said stem andplunger having communicating circulating passages therethroughterminatin at the seating surface on the nose of the p unger.

6. A construction as set forth in claim 1 wherein the thieves consist ofsharp rimmed cups having interior annular shoulders.

7. A construction as set forth in claim 1 wherein the thieves consist ofsharp rimmed cups with outlets at the bottom and having interior annularshoulders.

8. The construction set forth in claim 2 in combination with means fordetermining at -a remote point when the plunger has reached the end ofits stroke for pressing the thieves outwardly.

LEROY H. PERRY. WALTER F. WOODMAN.

